A novel vaccine has protected two chimpanzees from infection with HIV, the virus that causes AIDS. Though chimps can become infected with this virus, they rarely develop any of the symptoms of AIDS.

Researchers gave two chimps intramuscular injections of the DNA vaccine, which is made from genetic material resembling that of HIV. The vaccine spurs muscle cells to crank out HIV proteins. Because of genetic alterations the researchers introduced, these proteins aren't likely to cause disease; however, they may spark an immune response, says David B. Weiner of the University of Pennsylvania in Philadelphia.

Weiner and his colleagues gave a third chimp an injection without the genetic material, then gave each of the three chimps a massive dose of HIV.

Using a standard test that measures the amount of virus in the bloodstream, the team failed to find any evidence of HIV in the two vaccinated chimps. So far, that protection has lasted a year, Weiner says. In contrast, the control chimp shows infection with HIV. The study appears in the May Nature Medicine.

"This approach seems promising and clearly warrants further investigation," observes Ronald C. Kennedy of the University of Oklahoma Health Sciences Center in Oklahoma City in an accompanying commentary

Weiner's group and other scientists are now testing the vaccine to see whether it protects uninfected people at high risk of AIDS (SN: 2/17/96, p. 100). The researchers are also studying whether the vaccine will benefit people already infected with HIV "It appears to be boosting immune response in those patients," Weiner told Science News.

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